"To be clear, Deb and I always wanted to adopt. So that was always in our plan," the 44-year-old Aussie explained. "We didn't know where in the process that would happen, but biologically, obviously, we tried and it was not happening for us, and it is a difficult time. We did IVF, and Deb had a couple of miscarriages. I'll never forget it, the miscarriage thing -- it happens to one in three pregnancies, but it's very, very rarely talked about."

"It's almost secretive, so I hope Deb doesn't mind me bringing it up now," he continued. "It's a good thing to talk about it. It's more common, and it is tough. There's a grieving that you have to go through."

From the moment their son was born, Jackman said, "all the heartache just melted away." (The couple wed in 1996; Oscar was born four years later.)

"Many of you are parents; you guys know you can't prepare for that moment. Nothing can prepare you," the People's Choice Award nominee added. "You can't even explain how incredible it is, and that avalanche of emotion that comes and how it opens up your heart, how it frustrates you, how it angers you, how everything is just all the sudden, how alive you are as a parent."